Ousmane Dembele's Barcelona debut against Espanyol in photos

Lionel Messi scored a hat trick to lead their 5-0 win over crosstown rivals Espanyol on Saturday, making them the only side so far to win their first three games in La Liga.

Messi opened the scoring at Camp Nou when he received a pass from Ivan Rakitic in what appeared to be an offside position.

Defender Gerard Pique and Luis Suarez added late goals, the latter set up by debutant Ousmane Dembele, as Barcelona maintained the only 100 per cent record in the division. He continues to show that there'll be a lot of Messi for a while yet.

"We haven't had a good time at the Nou Camp recently, it's always hard and we have really struggled to win there, even to pick up a point, but I believe we can get something positive this time", said Espanyol midfielder Victor Sanchez.

However, the 22-year-old custodian could not repeat similar heroics during Barca's next effort on goal, which was fortunate to say the least, as Messi was on hand to simply tuck away his second of the evening following Jordi Alba's squared ball.

The visitors missed another great chance to reduce the deficit early in the second half when full-back Alba inadvertently laid the ball off to Piatti as Marc-Andre ter Stegen had come out to collect a long ball up field.

Uruguay forward Suarez, who only returned from global duty on Friday, looked to be having one of those nights as he sent a cut-back from Messi over from six yards.

Messi completed his hat-trick after 65 minutes as he was in the right place to fire home from Alba's cut-back.

Things are looking rosy at the Camp Nou.

Barcelona made all the early running but suffered a scare in the 21st minute when Sergio Busquets booked for cynically pulling back Leo Baptistao after his misplaced pass threatened to give the Espanyol forward a route to goal.